The present invention relates to a propellant-free inhalable formulation of a pharmaceutically acceptable salt of tiotropium dissolved in water or a mixture of water and ethanol, in conjunction with at least one other active substance preferably administered by inhalation, and propellant-free inhalable aerosols resulting therefrom. The formulation according to the invention is particularly suitable for administering the active substance by inhalation, especially for treating asthma and chronic obstructive pulmonary disease (COPD).
Tiotropium, chemically (1α, 2β, 4β, 5α,7β)-7-[(hydroxydi-2-thienylacetyl)oxy]-9,9-dimethyl-3-oxa-9-azoniatricyclo[3.3.1.02,4]nonane, is known as tiotropium bromide from European Patent Application EP 418 716 A1. The bromide salt of tiotropium has the following chemical structure: 
The compound has valuable pharmacological properties and is known by the name tiotropium bromide. Tiotropium and its salts are highly effective anticholinergics and can provide therapeutic benefit in the treatment of asthma or COPD (chronic obstructive pulmonary disease). The monohydrate of tiotropium bromide is also pharmacologically valuable. Both compounds are a preferred object of the present invention.